Automatic



A ril 7, 1953 H. E. DAHLSTROM EI'AL AUTOMATIC WORK STOP FOR PUNCH PRESS DIES Filed Nov. 17, 1949 FIG.2

INVENTOR. HARRY E. DAHLSTROM JOHN L. OLSON FIG. 5

ATTORNEYS Patented Apr. 7, 1953 UNITED STATES AT ENT OFFICE.

-2,633,915 An'roMA'rIoWoRK s'roP'FoRPUNcH PRESS DIES Harry EQDamSn-Om and John nelson,

. Minneapolis, Minn.

' Kpis'licationTNoveinber 17, 1949, serial noirziis're 4-" Claims.

I This invention relates to'punch' presses and dies; andfparticularly to a stop mechanism associated withthe dies of the press and operated'by action of the punch for gauging and precisely controlling the intermittent movement of the sheetimetal or other strip stock as the latter'is manually 'or automatically fed through 'the die for each successive punching operation. I

*It is an objectof our invention to provide automatic stcp mechanism of the class described,

which may be quicklyand easily applied to'va'rifcustypes of dies, which is readily and accurately responsive to theaction of 'the press and which is adapted to stop the stock in a desiredprecise relationship after each successive operation of'the punching mechanism "causing the stock to be precisely helcl during the next punching operation. A further objeetis the provision of a work or "stockestop of the class described'which isreadily "adjustable for blanking dies of various dimensions and size, which may be readily'app'lied to the stripper plate of such dies and which comprises a'minimum number of Working parts, essentially a spring fulcrum, mountingand tens,ioning"mem- *ber andan actuating leverjmounted therein.

lnother 'objectis the provision ofan automatic 'fwork stop'of theclass described wherein'the stop- "carrying lever is longitudinally slidableby hand inanipnlation 'for' adjustment to accommodate andwith the punch i extreme pos'ition'and havineourstop'applie'dthereto; I II I I Fig 2 is a top plan view of the die set' w ith-the 'punch removed showing an embodiment of our 'in'ventionapplied; I I I Fig.13'isa bottomplan view offtheessential elements of our automatic stop detached;

M Fig. l is a side elevation of thesaine;

. Fig. 5"is afragmentaryend elevation of "the combination clip and attachment member for my conventional manner and simplified form' preeminence clip iulcrum and attachment member *for 'the stop-bar;- and Fig. '7 'is-a fragmentary s'ide elevatiori bfthe same with the barf therein.

As shown in thedrawings, oui w'oik stop mechanism is applied to aeonvemiomr setof' dies o'f a punch press having the usual horizontal bed plate 6- on which ismountedthe 's'upporti ngdie l and stripper plate 8. Stripper pm-es s made in f "two sections having a transverse work-guidin channel fliz' form'ed therebetween through which th st'ock may be interinittently run 'or" projected. The stripper fplate 3 is slidably mou'nted on a pair"'of upstanding leader pins 9 and coil s'p'rin'gs tllsur'round at least two of said leader pins. interposedlbetweefi the base plate andstripp'er plate to urgeithestripper plate upwardly. suitable elements-H area-fixedto the supporting die land the baseplateas desired.

Above the lower dies and stripper plate is mounted a conventional type of punch plate I2 having at its rear aipair 0f"large, isliding=sleeves !2a which surround the vertical leader-pins "I 3 with working clearance. Punch plate l-2 carries in depending relationtheretotheusual punch-12b which is vertically aligned with-the-female "dies disposedtherebelow. All -of said above recited structure is convehtio'nalin di-sets for punch presses.

' Gur'autornatic work st'op mechanism is extremely -siinple', comprising as essential parts an elongatedleverb'ar l Marrying. apivoted upstanding stop pin I5; and a"conibination-mounting plate, fulcrumandfspring fiieinbei BI .Leveribar M is preferahly"irrtheffoini o'f a rigid; straight narrow 'bar''dis'pbsed substantially horizontally and edgewise withre'spect"tothebase plate and "stripper platen Thebaris of'small' oblongcrass section andpreferably hasiormedin the upper longitudinal "edge thereof, ase'ries of retaining notches i fi afor eng gemenrwnh semen, depend in'g detent l'ta formed inthe'u'p'per portion'of the -cornbination clip; fiilcrum andmoun'tingmeniher.

At th'e inner endo'f lever bar l'l th estop do e '15, as shown in the formof' airtipstantling -stud or pin,- is pivoted" by a rivet 'or other nreans lidg said dog as "shown, navi'nge bifurcated attachment portionorvclevis v15b which stra'ddles the extr'ernity. ot lever b'ar l 4 and: is pivotally secured thereto with freedom forswingingon'a horizontal axis disposed normal to ithe side-.surfacesof the bar. a

T e combinationclip. fulcrumandzattach'ment I member I it is preierablys-made=from-aanizintegrel pieceof spring; metalasuchias steel and ahavingnn upper fiat attachment plate 16b provided with 3 apertured ears through which screws I8 may be inserted to threadedly engage tapped sockets in the stripper plate for clamping the combination member I6 against bottom of the stripper plate and adjacent the forward edge thereof. The spring member I6 is curved outwardly and downwardly from the outer edge of the attachment plate I6b to form a lever-accommodating arcuate portion 160 and this medial or lever-accommodating portion is slotted circumferentially as clearly shown in Figs. 2 and 3. The integral spring member is then formed at its end disposed oppositely to the attachment plate IBb into a levergripping channel lBd. This channel is preferably of a depth at its extremity slightly less than the height of the lever bar [4 and is of a width to snugly accommodate the cross-sectional shape of bar I4 to center the bar in operation and urge the same to the desired transverse position with reference to the bottom of the stripper plate 8. The detent Isa which is struck up from the stock of attachment plate I6b is in the form of a substantially straight edge adapted to snugly fit any one of the notches I la at the upper edge of lever bar I4 and acting as a fulcrum for the lever Hi during operation. The fulcrum edge I6a as clearly shown in Fig. 5, is inclined slightly from the horizontal to produce a swinging action of bar I4 distorted from the vertical. The bowed spring member I6 is shaped and bowed in such manner as to be tensioned rather strongly when thelever bar I4 is slipped through the slotted accommodating portion I50 and through the leverretaining channel I6d, whereby the inner end of the lever is normally urged upwardly as shown in Figs. 1 and 4. The gripping channel Ifid is offset slightly as shown in Fig. in its inner contour with relation tothe slot between the U- shaped portions I60 to accommodate in the position shown, the lever I4 when held in normal work-stopping position, as shown in Fig. 1. The ofiseting of this channel with the biasing or inclination of the edge of fulcrum detent Ilia causes the lever bar I4 when the dog is released from the hole in the workpiece to twist at its inner end from left to right, facilitating the movement of the work strip to the next predetermined position. The dog I5 fits with clearance through a vertical hole formed in the lower section of stripper plate 8 and this hole and its relationship with the stripper plate and dies is formed when the dies are made and set up so that the dog will be positioned in work-stopping relation snugly against an end of the punched work towards the receiving end of the stock strip as shown in Fig. 2, thereby retaining the stock strip in precise relation with the dies and stripper plate for the next punch operation.

As shown in the drawings, a set of dies for a simpler blanking operation is provided adapted to cut out a substantially key-shaped plate from a. strip of sheet metal. The stop dog I5 is adapted to engage the extremity of the opening formed after blanking operation.

To release the stop dog I5 from engagement with the work as the punching operation takes place, an upstanding striker arm I9 is provided at I the outer edge of the bed plate 6 as shown being in the form of a metal arm having an outturned upper extremity and having its lower end rigidly affixed as by screws to the forward edge of its fulcrum Ito asthe stripperplate Bis moved 4 downwardly by the action of the punch and punch plate.

In use, our automatic stock mechanism is readily adjusted for the particular set of dies to be used and attachment plate I6b of the combined spring clip member is secured appropriately to the underside of the stripper plate by tapping or drilling the plate at opposite points for insertion of the attachment screws I8. The length of lever bar I 4 extending inwardly of fulcrum I6a may be readily adjusted as desired by merely forcing the tensioned end lBb of the spring clip downwardly and sliding the lever bar to the desired adjusted position with the detent and fulcrum IGa engaging the opposite notch. The bottom of the stripper plate is then drilled to accommodate the stock dog I5 in precise position for engagement of said dog with an opening at the guide-receiving end of the punched out portion of the piece of work. On relatively small die sets the outer end of lever bar I4 may be cut off if desired so that it will not objectionably protrude from the punch press and die.

In operation, the peculiar and simplified construction of the multi-function spring clip I6 not only receives and retains the simplified lever bar I4 but applies spring tension to the inner end of said bar to urge the same upwardly into stock stopping or looking position. In addition, the spring clip because of the confining channel 16d retains lever bar l4 and urges the same to a correct position slightly out of perpendicular to the common center line between the attachment aperture of the fiat attachment plate I6b of the clip which usually is parallel to the outer edge of the stripper plate. As the stripper plate is depressed in the installation of Figs. 1 and 2, the outer portion of the lever bar It is struck by upstanding plate or arm I9 which efiects the actuation of the lever bar to release the dog pin I5 from the aperture guide in the work strip. Immediately thereafter, due to the bias laterally upon the bar I i effected through the inclined fulrcum edge I61; and the relative positioning of the confining channel Ifid (see Fig. 5) the bar is caused to laterally shift at its inner end from left to right so that the dog pin cannot enter the same stop location in the work by the return stroke of the press. This action is exceedingly important to perfect functioning of our structure and allows the work to be moved to the next stop position where the pin I5 under the influence of the spring clip moves upwardly to precise alignment with the next aperture. Thus, the work is held in precise desired position through the initial portion of the next blanking or punching operation. As the punch plate and punch move downwardly depressing in said movement stripper plate 8, the outer portion of lever bar I 4 strikes the upstanding striker plate or arm I9 which actuates the lever to downwardly swing the inner dog-carrying end thereof, thereby momentarily releasing the work strip after the punch is made and enabling the work strip either by manual feeding or automatic feeding to be progressed to a position for next receiving the punch.

In Figs. 6 and '7 a somewhat different and simplified form of combination clip and fulcrum is illustrated on an installation wherethe clip is secured to an upper surface of a movable member such as a stripper plate. The clip in this form indicated as an entirety by the numeral I! has a flat attachment portion Ilb apertured at the ends thereof to form ears for screw attachmentto a plate and it hasan arcuate slotted bar .5 confining portion l'lc, the slot being of a width greater than the thickness of the bar M for permitting restricted shifting of the bar therein. The clip I! instead of employing a U-shaped confining channel for retention and seating of the bar at the opposite side of the fulcrum or detent Ila is merely slotted for a distance sufficient to accommodate the width of the bar, said slot very closely confining the bar as shown in Figs. 6 and 7. The slotted confining portion of the clip is indicated by the numeral lid. The slot is offset slightly with reference to the center line of the slotted forward portion llc in the manner illus trated in Fig. with reference to the form first described. The fulcrum detent ila is struck up from the body of the clip and is formed substantially identically with the fulcrum detent of the first form.

The operation of this second form of our device is identical with that of the form first described.

From the foregoing description it will be seen that our structure is readily and quickly applicable to all conventional types of punch press dies including in some instances forming dies as well as blanking or piercing dies.

It will further be seen that with an irreducible minimum of parts, we have provided a highly efficient automatic stop adapted to be manufactured at very low cost and producing accurate and efiicient results.

it will of course, be understood that various changes may be made in the form, details, arrangement and proportions of the parts without departing from the scope of our invention.

What we claim is:

1. An automatic work strip stop for the dies of a punch press having in combination, a multiple function spring clip member having an attachment element for securing the same to the stripper plate of a die set and having a resilient leverengaging element for retaining and positioning a lever bar, said clip having a fulcrum element protruding from the body thereof and opposed to said lever-engaging element, a lever arm having a cross sectional shape fitted to the leverengaging element of said spring clip, said spring clip including integrally formed means constituting a spring member extending outwardly from said attachment element and curved reversely for tensioning said lever-engaging element to swing said lever arm in a vertical direction and work stop means connected with the inner end of said lever arm shaped and constructed to pass through a portion of said stripper plate into engagement with an aperture or shoulder portion of a punched piece of work.

2. An automatic work strip stop for the dies of a punch press having in combination, a multiple function spring clip member having an attachment element for securing the same to the stripper plate of a die set and having a bowed tensionable element constituting a spring member extending outwardly from said attachment element and curved reversely with respect thereto and having a channel element for engaging and positioning a lever bar, said clip having a fulcrum edge protruding from the body thereof adjacent said attachment element and opposed to said channel element, a lever arm having a cross sectional shape adapted to fit said channel element of said clip and of a thickness for interposition between said fulcrum element and said channel element with application of tension to said bowed element, and stop means connected with one end of said lever arm shaped and constructed to pass through a portion of said stripper plate into engagement with an apertured or shouldered portion of a punch piece of work and normally urged thereagainst by said channel element in response to the spring tension of said bowed tensionable element.

3. The structure set forth in claim 2, said spring clip constituting an integral member with said bowed tensionable element provided with a medial slot for accommodating said lever arm and a striker element having means for attachment to one of the principal elements of a die set for alignment with the outer portion of said lever arm to actuate said arm for retracting said stop means during the downward movement of the punch plate of a die set.

4. An automatic work strip stop for the dies of a press having in combination a multiple function spring clip having an attachment element for afiixation to a member of a die set and having a lever-engaging element resiliently connected with said attachment element and generally opposed thereto for snugly straddling, retaining and positioning a lever bar, said clip having a fulcrum element protruding from the body thereof generally towards said straddling leverengaging element and having a lever-arm-engaging edge diagonal somewhat with respect to the general plane of said attachment element, a lever arm having a cross sectional shape fitted to said straddling lever-engaging element, work stop means connected with the inner end of said lever arm, the resilient connection of said leverengaging element with the body of said clip constituting a spring member extending outwardly from said attachment element and curved re- HARRY E. DAHIJSTROM. JOHN L. OLSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,219,060 West Oct. 22, 1940 2,314,271 Garberding Mar. 16, 1943 FOREIGN PATENTS Number Country Date 148,684 Great Britain Aug. 5, 1920 

